﻿// 
// UseVarKeyword.cs
//  
// Author:
//       Mike Krüger <mkrueger@novell.com>
// 
// Copyright (c) 2011 Mike Krüger <mkrueger@novell.com>
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
using System;
using System.Linq;
using ICSharpCode.NRefactory.PatternMatching;
using System.Threading;
using System.Collections.Generic;

namespace ICSharpCode.NRefactory.CSharp.Refactoring
{
	[ContextAction("Use 'var' keyword",
	               Description = "Converts local variable declaration to be implicit typed.")]
	public class UseVarKeywordAction : CodeActionProvider
	{
		internal static readonly Version minimumVersion = new Version (3, 0, 0);

		public override IEnumerable<CodeAction> GetActions(RefactoringContext context)
		{
			if (!context.Supports(minimumVersion))
				yield break;
			var varDecl = GetVariableDeclarationStatement(context);
			var foreachStmt = GetForeachStatement(context);
			if (varDecl == null && foreachStmt == null) {
				yield break;
			}
			yield return new CodeAction(context.TranslateString("Use 'var' keyword"), script => {
				if (varDecl != null) {
					script.Replace(varDecl.Type, new SimpleType ("var"));
				} else {
					script.Replace(foreachStmt.VariableType, new SimpleType ("var"));
				}
			}, (AstNode)varDecl ?? foreachStmt);
		}
		
		static VariableDeclarationStatement GetVariableDeclarationStatement (RefactoringContext context)
		{
			var result = context.GetNode<VariableDeclarationStatement> ();
			if (result != null && result.Variables.Count == 1 && !result.Variables.First ().Initializer.IsNull && result.Type.Contains (context.Location) && !result.Type.IsVar ())
				return result;
			return null;
		}
		
		static ForeachStatement GetForeachStatement (RefactoringContext context)
		{
			var result = context.GetNode<ForeachStatement> ();
			if (result != null && result.VariableType.Contains (context.Location) && !result.VariableType.IsVar ())
				return result;
			return null;
		}
	}
}

